Cup-like insole

Abstract: A cup-like insole includes a body (2) of elastic material whose bottom surface having a shape to fit to a bottom member of a shoe therein having a flat portion (5) and a concave side wall portion (6) formed integrally therewith extending from the area corresponding to the inner arch portion (3) of the foot to the area corresponding to the outer lateral side (4) of the foot through the area corresponding to the heel portion (7) of the foot, an impact cushioning material having bouncing putty and disposed on the upper surface of the side wall, and a sheet made of either woven fabrics, unwoven fabrics, or leather covering over the impact cushioning material to secure it to the body. The cup-like insole according to the invention provides improved fitness of the heel portion of a shoe to stabilize the heel of the wearer.

Description: TECHNICAL FIELD This invention relates to a cup-like insole and more particularly relates to a cup-like insole having improved fitness of the heel portion of a shoe to stabilize the heel of the wearer. BACKGROUND OF THE INVENTION A conventional insole, in general, consists of a body made of materials such as synthetic resin foam or elastomer covered with leather, woven fabrics, unwoven fabrics or the like adhisively bonded thereto. There are some types of such insoles which includes one having a flat shape cut out of a sheet material in a shape of the foot, one having a raised portion in the area corresponding to the arch portion of the foot, and one having a raised portion surrounding the heel of the foot so as to fit thereto. The US 4,541,186 describes a lightweight, flexible gymnastic shoe, which includes an upper formed of a lightweight synthetic fabric, a sole of a relatively thin resilient material, a liner located inside said upper, a metatarsal pad located along the liner and an arch support formed of a built up area of material positioned below the medial arch area. These insoles are employed for the purpose of improving the fitness of the foot, especially the heel of the foot within a shoe by filling the space between the foot and the interior of the shoe, thereby improving the stability of the heel of the foot while walking or running. The most common type of resin foam utilized for the insoles is the one which can be deformed by compression applied by the heel of the wearer so as to conform to the shape of the heel and bounces back to the original shape when the wearer takes off the shoe as described in, for example, Japan utility model public disclosure Sho 59-42892 and Japan utility model public disclosure Sho 59-23528. There is another type of resin foam which does not bounce back to the original shape once compressively deformed even when the wearer takes off the shoe as described in, for example, Japan utility model public disclosure Sho 61-16807 and Japan utility model public disclosure Sho 62-28163. Furthermore, there is another type disclosed in Japan utility model public disclosure Sho 62-7126 which is formed by mixing uncured synthetic foam with curing agent, pouring the mixture into a bag-like sheet, and placing the foot of the wearer on the mixture filled bag to press the shape of the foot thereto, whereby an insole which has a close fitness to the foot is formed when curing process is completed. Most of these conventional insoles utilize an impact cushioning layer or space filler made of the synthetic foam such as polyurethane, polyolefin, or the like utilizing their pysical property of compression-deformation. Therefore, when a wearer puts on a shoe having such insole, the impact cushioning layer of the insole made of synthetic foam is deformed due to the weight of the wearer to comform to the shape of the foot of the wearer. The impact cushioning layer absorbs the impact force applied thereto from the ground during walking and running. However, the impact cushioning layer formed from the synthetic foam is easily deformed by the pressure applied by the heel and can not prevent rolling of the heel. Therefore, the heel is unstable during walking and running, resulting in rolling of the ankle, which may cause excessive pronation and supination of the foot that can hurt the foot of the wearer. In addition, the commonly used materials used to form the impact cushioning layer or the space filler of the insoles such as polyolefin resin foam and chloroprene rubber foam often exhibit so-called permanent set due to the compressive force applied through wearing the shoe repeatedly. That can cause deterioration in its flexibility and the ability to restore the original shape , and therefore, it will no longer function as the impact cushioning layer or the space filler. SUMMARY OF THE INVENTION A cup-like insole according to the invention as claimed in claim 1 is of the type which is installed within a shoe. It includes a body (2) of elastic material whose bottom surface having a shape to fit to a bottom member of a shoe therein having a flat portion (5) and a concave side wall portion (6) formed integrally therewith extending from the area corresponding to the inner arch portion of the foot (3) to the area corresponding to the outer lateral side of the foot (4) through the area corresponding to the heel portion of the foot (7), an impact cushioning material (8) having bouncing putty and disposed on the upper surface of said concave side wall portion (6), and a sheet (9) made of either woven fabrics, unwoven fabrics, or leather covering over the impact cushioning material (8) to secure it to the body and wherein Said impact cushioning material (8) is a pad containing bouncing putty therein which plastically deforms easily when a stress is applied more slowly and exhibits a high degree of bounce under a stress applied suddenly. It may be comprised of a pad including a bag-like sheet member made of polyurethane, silicone rubber, polyvinylchloride or the like with the bounching putty contained therein, this not being comprised in the invention as claimed. According to the invention, the impact cushioning material is formed from. open-cell foam made of, for example, polyurethane, and impregnated with the bouncing putty. The pad may be formed with stacking parts of sheets impregnated with the bouncing putty, each of which is cut into a flat horseshoe shape and bonded together into a three-dimensional horseshoe shape. Alternatively, the pad may be formed from a unitary block of foam impregnated with the bouncing patty which is cut into the three-dimensional horseshoe shape. It can be formed in either way depending on its usage. Furthermore, in order to enhance its function as a cup-like insole, the shoe is preferrably provided with a cup-like stabilizer or a heel counter made of relatively hard synthetic resin positioned at a bottom member of a shoe in its heel area. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, Figure 1 is a plane view of an embodiment of a cup-like insole according to the invention; Figure 2 is a cross-sectional view taken along line A-A of Figure 1; Figure 3 is a perspective view of a cup-like insole according to the invention; Figure 4 is a view showing how to use a cup-like insole according to the invention; Figure 5 is a cross-sectional view taken along line B-B of Figure 4; and Figure 6 is a view showing foam impregnated with bouncing putty. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a cup-like insole according to the invention is described with reference to the drawings. As can be seen in Figure 2, a cup-like insole according to the preferred embodiment includes a body 2 of elastic resin having suitable rigidity such as EVA, urethane foam or the like whose bottom surface having a shape to fit to a bottom member of a shoe therein. It has a substantially flat portion 5 and a side wall portion 6 formed integrally therewith extending from the area corresponding to the inner arch portion of the foot 3 to the area corresponding to the outer lateral side of the foot 4 through the area corresponding to the heel portion of the foot 7. An impact cushioning material 8 formed substantially into a shape of a horse-shoe is disposed on the upper surface of the side wall portion 6 of the body 2. Bouncing putty particles 14 dispersed in open-cell foam is utilized for the impact cushioning material 8. In the embodiment, as can be seen in Figure 6, the impact cushioning material 8 includes the open-cell foam 13 which is impregnated with the bouncing putty solved in a solvent that is volatilized after the impregnation. When a pressure is applied, the foam itself is compressed, whereby the bouncing putty particles 14 dispersed in the open-cell foam agglomerate due to its compression. Upon completion of the deformation of the impact cushioning material 8 under the pressure, it will have the same behavior as that of the bouncing putty itself. The impact cushioning material 8 is disposed on the side wall portion 6 of the body 2 extending from the area corresponding to the inner arch portion of the foot 3 to the area corresponding to the outer lateral side of the foot 4 through the area corresponding to the heel portion of the foot 7, covered with a fabric 9 such as a double russel fabric made of polyester and is stitched to the body 2 to secure it thereto. Not only the impact cushioning material 8 but also the flat portion 5 of the body 2 may be covered with the fabric 9. In this preferred embodiment, woven fabrics are used. However, other materials having resistance to wear and high stretchability such as unwoven fabrics, leather, artificial leather or the like can also be used. In use, the cup-like insole 1 constructed as described hereinabove, is disposed on a inner bottom surface 11 of a shoe 12 as shown in Figure 4. Since the shoe 12 is provided with a cup-like stabilizer 15 having a higher hardness than that of a bottom member of the shoe 12 positioned at its heel area, the pressure applied by the heel of a wearer is transferred to the impact cushioning material 8 without escaping to the bottom member of the shoe which makes it possible to exhibit higher effect of the bouncing putty . Although in this preferred embodiment, the cup-like stabilizer 15 is used, a heel counter providing the same effect can be used. Futhermore, in the case where the shoe is not provided with the cup-like stabilizer 15 or the heel counter, the same effect can be achieved by utilizing the cup-like insole 1 whose the side wall portion 6 of the body 2 is formed from a material having high hardness such as nylon, urethane, PVC, or the like. The cup-like insole constructed as described hereinabove provides the following effects. Since the cup-like insole is made of the elastic resin having a suitable rigidity, it allows the impact cushioning material 8 disposed on the side wall portion 6 extending from the area corresponding to the inner arch portion of the foot 3 to the area corresponding to the outer lateral side of the foot 4 through the area corresponding to the heel portion of the foot 7 to fully deform to comform to any shapes of the heel. Furthermore, once plastically deformed, due to the property of the bouncing putty, the impact cushioning material 8 exhibits a high degree of bounce under suddenly applied stresses holding the shape of the heel of the foot, thereby stabilizing the heel of the wearer. Because the cup-like stabilizer 15 or the heel counter having high hardness is provided with the shoe 12, pressure from the heel of the wearer is not liable to escape through the bottom member of the shoe and is applied to the impact cushioning material 8, whereby the impact cushioning material 8 can be plastically deformed, thereby exhibiting its higher effect to fit to the heel of the wearer. Furthermore, in case of a shoe without the cup-like stabilizer, the impact cushioning material 8 can be plastically and fully deformed by forming the side wall portion 6 of the body 2 of the cup-like insole 1 with a material having high hardness. In addition, the impact cushioning material 8 made of the open-cell foam impregnated with the bouncing putty provides a self-supporting capability to the bouncing putty provided that no permanent set in fatigue occurs, and the use of it results in significant reduction in a weight of the impact cushioning material 8 and hence, of the shoe, compared with the one with the bouncing putty contained in a bag-like sheet. The present invention has thus been shown and described with reference to a specific embodiment. However, it should be noted that the present invention is in no way limited to the details of the described arrangements but changes and modifications may be made within the scope of the appended claim.

Claims: A cup-like insole to be disposed within a shoe, comprising: a body (2) of elastic material whose bottom surface having a shape to fit to a bottom member of a shoe therein having a flat portion (5) and a concave side wall portion (6) formed integrally therewith extending from the area corresponding to the inner arch portion of the foot (3) to the area corresponding to the outer lateral side of the foot (4) through the area corresponding to the heel portion of the foot (7); characterized by an impact cushioning material (8) having bouncing putty and disposed on the upper surface of said concave side wall portion (6); and a sheet (9) made of a material selected from the group consisting of woven fabrics, unwoven fabrics, or leather covering over the impact cushioning material (8) to the body to secure it to the body, and wherein said impact cushioning material (8) is formed from open-cell foam impregnated with the bouncing putty.

Inventors: KITA KENJIRO, KITA, KENJIRO, KITA, KENJIRO, C/O MIZUNO CORPORATION
Applicants: MIZUNO KK, MIZUNO CORPORATION
Application year: 1994
Main classification: A43B17
IPC codes: A43B17, A43B13